Abstract

The rates at which people smoke cigarettes during different periods of the day were obtained from three occupational groups. Group 1 consisted of those working at the main London production site of a food processing factory, Group 2 consisted of those in the administrative offices of the same company; there are smoking restrictions at both. Group 3 consisted of workers in the offices of a London borough where there are no smoking restrictions. Replies were received from 3174 people, or 88% of those approached. There was a higher proportion on non-smokers (over 70%) among the two groups of office workers than among the food processing workers (about 55%). Smokers in Group 3 recorded somewhat higher average cigarette consumption than those in Groups 1 and 2. During different periods of the day, the maximum hourly rate of cigarette smoking was about three times the minimum rate. For Groups 1 and 2 the maximum rate was consistently during the interval between leaving work and going to bed. In contrast, the maximum rate for Group 3 was consistently during the afternoon, while at work, and the rate between leaving work and going to bed was similar to the rate for the day as a whole. Results will help in deciding the time of day at which blood for carboxyhaemoglobin estimations should be taken.